Copper sulfide: Difference between revisions

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There are a number of copper sulfides like Cu2S, Cu2-xS CuS and even CuS2, although the latter is a high pressure phase. From the stoichiometry it would seem that Cu2S is Cu+ (d10) monovalent cuprous sulfide whereas CuS is cupric Cu2+ (d9). However, this is not the case. Because the Cu2+ ion is a relatively strong oxidizer, it is able to oxidize sulfide to disulfide ions:

   2Cu2+ + 2S2-  --> 2Cu+  + 2S- --> 2Cu+ + (S2)2-

In this process the one missing d-electron ("hole") of the d9 configuration is transferred to the sulfur. Sometimes that leads to sulfur pair formation sometimes not.

The result is that Cu is essentially monovalent in all these compounds. What lies near the Fermi level is a valence band predominantly S 2p character

Most of them are metallic because if the pairformation is incomplete the remaining holes in the valence band lead to metallic conductivity.

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+There are a number of [[copper]] '''sulfides''' like Cu2S, Cu2-xS CuS and even CuS2, although the latter is a high pressure phase.
-Put your text for the new page here.
+From the [[stoichiometry]] it would seem that Cu2S is Cu+ (d10) monovalent cuprous sulfide whereas CuS is cupric Cu2+ (d9). However, this is not the case. Because the Cu2+ ion is a relatively strong [[oxidizer]], it is able to oxidize sulfide to [[disulfide]] [[ion]]s:
-There are a number of copper sulfides like Cu2S, Cu2-xS CuS and even CuS2, although the latter is a high pressure phase.
-From the stoichiometry it would seem that Cu2S is Cu+ (d10) monovalent cuprous sulfide whereas CuS is cupric Cu2+ (d9). However, this is not the case. Because the Cu2+ ion is a relatively strong oxidizer, it is able to oxidize sulfide to disulfide ions:
 Cu2+ + 2S2-  --> 2Cu+  + 2S- --> 2Cu+ + (S2)2-
 In this process the one missing d-electron ("hole") of the d9 configuration is transferred to the sulfur. Sometimes that leads to sulfur pair formation sometimes not.